Re: [PATCH] bpf, x32: Fix bug for BPF_ALU64 | BPF_NEG

[Daniel Borkmann]

On 04/28/2019 04:33 AM, Wang YanQing wrote:
> The current implementation has two errors:
> 1: The second xor instruction will clear carry flag which
>    is necessary for following sbb instruction.
> 2: The select coding for sbb instruction is wrong, the coding
>    is "sbb dreg_hi,ecx", but what we need is "sbb ecx,dreg_hi".
> 
> This patch rewrites the implementation and fixes the errors.
> 
> This patch fixes below errors reported by bpf/test_verifier in x32
> platform when the jit is enabled:
> "
> 0: (b4) w1 = 4
> 1: (b4) w2 = 4
> 2: (1f) r2 -= r1
> 3: (4f) r2 |= r1
> 4: (87) r2 = -r2
> 5: (c7) r2 s>>= 63
> 6: (5f) r1 &= r2
> 7: (bf) r0 = r1
> 8: (95) exit
> processed 9 insns (limit 131072), stack depth 0
> 0: (b4) w1 = 4
> 1: (b4) w2 = 4
> 2: (1f) r2 -= r1
> 3: (4f) r2 |= r1
> 4: (87) r2 = -r2
> 5: (c7) r2 s>>= 63
> 6: (5f) r1 &= r2
> 7: (bf) r0 = r1
> 8: (95) exit
> processed 9 insns (limit 131072), stack depth 0
> ......
> Summary: 1189 PASSED, 125 SKIPPED, 15 FAILED
> "
> 
> Signed-off-by: Wang YanQing <udknight@xxxxxxxxx>

Applied, thanks!